Mahanakorn University of Technology (Thai: มหาวิทยาลัยเทคโนโลยีมหานคร, short MUT) is a university in Thailand. The university was established on February 27, 1990 at Nong Chok District, Bangkok. as Mahanakorn College by Prof. Dr. Sitthichai Pookaiyaudom, former Dean of King Mongkut’s Institute of Technology Ladkrabang. The objective was to train engineering students in response to the severe shortage of engineers. MUT was then promoted to full university status under the new name Mahanakorn University of Technology .It is the first and still the only university in the country that operates its own low-orbit microsatellite (TMSAT).
This study proposes a numerical investigation of enhanced thermal performance in a circular tube equipped with periodically arranged, inclined delta wings (DWs) mounted directly on the inner tube walls. The turbulent airflow is evaluated for Reynolds numbers (Re) between 3000 and 21,000 utilizing the finite volume approach along with the Realizable k–ε turbulent model. The analysis is performed in two different phases: solid delta wings (DW) and punched delta wings (PDW). In the solid DW phase, the angle of attack (α) is kept constant at 45°, and geometric parameters include a set of four base/chord ratios (BR = 0.4 to 0.7) and four pitch ratios (PR = 0.5 to 1.5). The forward delta wing (F-DW) constantly outperforms the backward delta wing (B-DW) in terms of heat transmission enhancement, as indicated by comparative analysis of the DWs. In contrast to a smooth tube, the F-DW generates streamwise vortices that greatly boost fluid interaction and heat transmission, but at the sacrifice of rising pressure loss. The greatest Nusselt number (Nu) and friction factor (f) are realized with the F-DW at the narrowest pitch ratio (PR = 0.5) and its highest base ratio (BR = 0.7). Under baseline operating parameters of PR = 0.75 and Re = 3,000, the largest thermal enhancement factor (TEF) values of 2.79, 2.82, and 2.76 are achieved, with corresponding Nu ratios of 7.69, 8.79, and 10.34 for BR = 0.4, 0.5, and 0.6, respectively. In the second phase, a novel perforation approach is employed on the optimal F-DW (BR = 0.5, PR = 0.75) to establish a forward punched delta wing (F-PDW). This cutting-edge F-PDW attains a maximum TEF of 3.01 alongside a Nu ratio of 9.24. The findings show that, as contrasted to solid DWs and smooth tubes, the F-PDW greatly increases overall TEF, indicating its great potential for efficient, smaller heat exchanger applications.
The article conducts an experimental study into heat transfer and exergy characteristics of a tube-type heat exchanger contained with delta-baffle vortex generators to enhance convection heat transmission. There are two phases to the investigation: solid delta baffles (DB) and perforated delta baffles (PDB). In the first DB phase, the specific DB parameters of four relative pitches (PR = 0.75–1.5) and three blockage ratios (BR = 0.4–0.6) are explored for a broad variety of Reynolds numbers (Re) from 4760 to 29,260. The studies are performed at a consistent attack angle (α) of 45° utilizing a forward-inclined DB configuration (F-DB), which exhibits superior thermal performance relative to the backward-inclined DB configuration (B-DB). The F-DB markedly improves thermal performance in contrast to a plain tube, achieving peak friction factor (f) and Nusselt number (Nu) values up to 27.51 and 5.9 times above those of the plain tube, respectively. The optimal thermal enhancement factor (TEF) and exergy efficiency for the F-DB are 2.57 and 0.9933, respectively, attained at BR = 0.5 and PR = 0.75. In the second phase, forward perforated delta baffles (F-PDB) with an adjustable louver-flap angle (θ = 20°, 30°, 45°, and 60°) are generated by employing a novel perforation technique on the optimal F-DB cases. The F-PDB reaches a peak TEF of 2.68 at θ = 45°, outperforming values recorded in prior studies. Lastly, the experimental correlations for f and Nu have been formulated for both F-DB and F-PDB designs.
This study conducts an investigative exploration of thermal and hydraulic performance regarding hybrid inserts which combine perforated twisted tapes with vortex generator wings mounted inside circular tubes. The insert design makes use of both swirl flow and secondary vortex generation which breaks up the thermal boundary layer and boosts convective heat transfer rates. During this investigation, researchers utilized water as the working fluid at Reynolds number (Re) from 3000 to 21,000 to study the effect of three perforation diameter ratio (d/D) 0.143, 0.19, and 0.238 and respective Vortex generator (VG) edge cut ratio (a/D) 0.143, 0.19, and 0.238. Nusselt number (Nu) reach 182.3 % and thermal enhancement factor (TEF) achieve 1.68 at Re = 15,000 when using the enhanced tube compared to a smooth tube. The industrial application of larger VG openings at standard spacing produced a beneficial relationship between thermal performance and flow resistance when the pressure rise reached 345 %. The analysis of entropy generation showed heat transfer irreversibility gave way to frictional irreversibility when both perforation dimension and Re became larger. System design optimization prerequisites involved trade-offs which met Bejan number (Be) analysis trends. The Random Forest machine learning model combined with ANN and Linear Regression models contributed to thermal parameter prediction (Nu, f, TEF) by delivering a predictive accuracy level with less than 6.6 % deviation. The research leads to vital knowledge needed for developing compact heat exchangers integrating passive enhancement methods.
Vortex generators are effective devices for enhancing heat transfer rates in heating or cooling systems with minimal frictional losses via the production of streamwise vortices. This research effort presents the perforated double V-winglet (P-DVW) and looks at how it affects heat transmission and friction when mounted inside a heat exchange tube that is consistently heated for producing multiple vortices whereas its flow is turbulent. Optimizing thermal performance for increased energy savings and maximizing the Nusselt number (Nu) to minimize heat exchanger size are the major goals. Thermal characteristics, including generated entropy and exergy efficiency, are explored in depth. A Reynolds number (Re) that varies from 4760 to 29,270 is employed to explore the friction and thermal features of the tube. The P-DVW parameters encompass attack angles of alpha 2 = 15 degrees and alpha 1 = 30 degrees, four porosity ratios (Ah/Aw= 0, 0.0188, 0.0523, and 0.1026), and three pitch ratios, PR, (0.75, 1, and 1.25), while maintaining a constant winglet height. At PR = 0.75 and Ah/Aw = 0, the P-DVW exhibits peak f and Nu values around 23.83 and 5.31 times bigger than those of the plain tube, accordingly. Further, under the specified conditions, it yields minimal entropy production, while the optimal exergy efficiency is roughly 0.9829. The thermal effectiveness of P-DVW is anticipated to reach its maximum at 2.55 with NuR = 4.54 at Ah/Aw = 0.0523 and PR = 0.75 to reveal its actual benefits. Furthermore, the correlations off, Nu, and TEF were determined for the examined range of values.
This study aims to experimentally evaluate and compare the electrical–thermal performance of a 20-cell 18650 lithium-ion battery pack cooled by a pure phase change material (PCM) and a PCM/TiO2 nanoparticle composite to identify an effective passive thermal management approach for EV battery applications. Using a controlled charging–discharging system, thermocouple-based temperature mapping, and systematic tests across multiple C-rates (0.75 C–1.5 C), the study measures the variations in battery temperature, generated heat, and voltage behavior as functions of depth of discharge (DOD) and state of charge (SOC). The results show that the PCM/nanoparticle mixture markedly improves thermal conductivity, reduces peak temperature by approximately 8–10 °C compared with pure PCM, delays thermal saturation at higher C-rates, and enables a wider safe DOD range with reduced voltage sag and lower heat accumulation. Based on the experimental temperature/voltage trends in this study, limit DOD to ≤40–50% at high power (≈1.5 C), ≤50–60% at moderate power (≈1 C), and ≤60–70% at low power (≈0.75 C) (i.e., target SOC windows roughly 60–100% SOC at 1.5 C, 40–100% SOC at 1 C, and 30–100% SOC at 0.75 C), with an absolute practical upper DOD limit of ~70% to avoid frequent deep discharge damage; these limits keep peak temperatures below ~40–45 °C, reduce severe voltage sag near cutoff, and greatly extend cycle life because shallower cycling (e.g., 50% vs. 100% DOD) produces many times more cycles. These improvements enhance battery safety, performance stability, and cycle life, making the nanoparticle-enhanced PCM a practical, compact, and energy-efficient solution for passive battery thermal management in electric vehicles.
